What Is The Difference Between A Living And Nonliving? What Is The Least That Can Be Considered As Life?

First of all lets make clear what do I mean: An organism that would remain unchanged structurally drying a very small period of time,would be considered as nonliving for that period. When we say unchanged we mean of course that there are not taking place chemical reaction inside it.Maybe there isa single cell inside an organism thatis unchanged,but therest of the cells are changing. We say then that this organism has a dead cell but the organism as a whole is alive.Maybe this cell would be able to regain life if it reacts with the appropriate signals.